Do a quick Google search of "2010 Jeep JK 4.88 gearing MPG" you'll usually find pretty good feedback. Some owners claim they gained MPG some say it dropped. Really, MPG is all about the driver (no matter what setup). I know some people on stock Jeeps who claim 14-16 avg... I get 18-19mpg avg. Others on lifted jeeps get 10-12mpg (depending on setup) then others with a similar setup get 14-15 mpg... you get the idea.
Also, I'd figured being in TX where it's flat you're going to see different results as say someone who lives in a more mountainous area like Denver! Cheers and make sure to utilize that search bar in subsections before you make a post, this forum is a mega-archive of awesome info that has answers faster by searching than you would get making a post and waiting for the response! You can also revive those old threads if you feel necessary and ask new/additional questions
Oh yea, welcome to WAL! Cheers :beer: